Last weekend I watched
THE SPANISH CAPE MYSTERY (1935)
My favorite part about it is
it's from a novel by Ellery Queen
who is the fictitious author who also
stars in the movie AND his
traveling companion is reading
a book by him as well!
Furthermore, the California sheriff
sarcastically refers to him as
Chan and Philo (as in Charlie Chan
and Philo Vance) two other
fictitious detectives who also
have their own film series.
You need a detective to keep
track of the layers of reality.